/*!	 gamma.h
**	 Template Header
**
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
*/

#ifndef __SYNFIG_GAMMA_H
#define __SYNFIG_GAMMA_H

#include <cmath>

namespace synfig
{

/*!	\class Gamma
**	 This class performs color correction on Color classes.
**	\stub
*/
class Gamma
{
    float gamma_r;
    float gamma_g;
    float gamma_b;
    float black_level;
    float red_blue_level;

    unsigned char table_r_U16_to_U8[65536];
    unsigned char table_g_U16_to_U8[65536];
    unsigned char table_b_U16_to_U8[65536];

    float table_r_U8_to_F32[256];
    float table_g_U8_to_F32[256];
    float table_b_U8_to_F32[256];

public:
    Gamma(float x = 1): black_level(0)
    {
        set_gamma(x);
    }

    void set_gamma(float x);
    void set_gamma_r(float x);
    void set_gamma_g(float x);
    void set_gamma_b(float x);
    void set_black_level(float x);

    void set_red_blue_level(float x);
    void set_all(float r, float g, float b, float black, float red_blue = 1.0f);

    float get_gamma()const
    {
        return (gamma_r + gamma_g + gamma_b) * 0.33333333;
    }
    float get_gamma_r()const
    {
        return gamma_r;
    }
    float get_gamma_g()const
    {
        return gamma_g;
    }
    float get_gamma_b()const
    {
        return gamma_b;
    }
    float get_black_level()const
    {
        return black_level;
    }
    float get_red_blue_level()const
    {
        return red_blue_level;
    }

    void refresh_gamma_r();
    void refresh_gamma_g();
    void refresh_gamma_b();

    const unsigned char &r_U16_to_U8(int i)const
    {
        return table_r_U16_to_U8[i];
    }
    const unsigned char &g_U16_to_U8(int i)const
    {
        return table_g_U16_to_U8[i];
    }
    const unsigned char &b_U16_to_U8(int i)const
    {
        return table_b_U16_to_U8[i];
    }

    const unsigned char &r_F32_to_U8(float x)const
    {
        return table_r_U16_to_U8[(int)(x * 65535.0f)];
    }
    const unsigned char &g_F32_to_U8(float x)const
    {
        return table_g_U16_to_U8[(int)(x * 65535.0f)];
    }
    const unsigned char &b_F32_to_U8(float x)const
    {
        return table_b_U16_to_U8[(int)(x * 65535.0f)];
    }

    unsigned short r_F32_to_U16(float x)const
    {
        return (unsigned short)table_r_U16_to_U8[(int)(x * 65535.0f)] << 8;
    }
    unsigned short g_F32_to_U16(float x)const
    {
        return (unsigned short)table_g_U16_to_U8[(int)(x * 65535.0f)] << 8;
    }
    unsigned short b_F32_to_U16(float x)const
    {
        return (unsigned short)table_b_U16_to_U8[(int)(x * 65535.0f)] << 8;
    }

    const float& r_U8_to_F32(int i)const
    {
        return table_r_U8_to_F32[i];
    }
    const float& g_U8_to_F32(int i)const
    {
        return table_g_U8_to_F32[i];
    }
    const float& b_U8_to_F32(int i)const
    {
        return table_b_U8_to_F32[i];
    }

    float r_F32_to_F32(float x)const
    {
        return static_cast<float>(pow(x, gamma_r) * (1.0f - black_level) + black_level);
    }
    float g_F32_to_F32(float x)const
    {
        return static_cast<float>(pow(x, gamma_g) * (1.0f - black_level) + black_level);
    }
    float b_F32_to_F32(float x)const
    {
        return static_cast<float>(pow(x, gamma_b) * (1.0f - black_level) + black_level);
    }
}; // END of class Gamma

}; // END of namespace synfig

#endif